Zhang Jing, Cai Ge-Mei, Yang Lv-Wei, Ma Zhi-Yuan, Jin Zhan-Peng
School of Materials Science and Engineering, Education Ministry Key Laboratory of Non-ferrous Materials Science and Engineering, Central South University , Changsha 410083, Hunan, China.
Department of Chemical System Engineering, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Inorg Chem. 2017 Nov 6;56(21):12902-12913. doi: 10.1021/acs.inorgchem.7b01670. Epub 2017 Oct 9.
Single-component white phosphors stand a good chance to serve in the next-generation high-power white light-emitting diodes. Because of low thermal stability and containing lanthanide ions with reduced valence state, most of reported phosphors usually suffer unstable color of lighting for practical packaging and comparably complex synthetic processes. In this work, we present a type of novel color-tunable blue-white-yellow-emitting MgInPO:Tm/Dy phosphor with high thermal stability, which can be easily fabricated in air. Under UV excitation, the MgInPO:TmDy white phosphor exhibits negligible thermal-quenching behavior, with a 99.5% intensity retention at 150 °C, relative to its initial value at room temperature. The phosphor host MgInPO was synthesized and reported for the first time. MgInPO crystallizes in the space group of C2/c (No. 15) with a novel layered structure built of alternate anionic and cationic layers. Its disordering structure, with Mg and In atoms co-occupying the same site, is believed to facilitate the energy transfer between rare-earth ions and benefit by sustaining the luminescence with increasing temperature. The measured absolute quantum yields of MgInPO:Dy, MgInPO:TmDy, and MgInPO:TmDy phosphors under the excitation of 351 nm ultraviolet radiation are 70.50%, 53.24%, and 52.31%, respectively. Present work indicates that the novel layered MgInPO is a promising candidate as a single-component white phosphor host with an excellent thermal stability for near-UV-excited white-light-emitting diodes (wLEDs).
单组分白色磷光体很有可能应用于下一代高功率白光发光二极管。由于热稳定性低且含有价态降低的镧系离子，大多数已报道的磷光体在实际封装时通常存在照明颜色不稳定的问题，并且合成过程相对复杂。在这项工作中，我们展示了一种新型的具有高热稳定性的颜色可调的蓝白黄发射MgInPO:Tm/Dy磷光体，它可以在空气中轻松制备。在紫外激发下，MgInPO:TmDy白色磷光体表现出可忽略不计的热猝灭行为，在150°C时相对于其室温初始值强度保留率为99.5%。磷光体基质MgInPO首次被合成并报道。MgInPO以C2/c（编号15）空间群结晶，具有由交替的阴离子层和阳离子层构成的新型层状结构。其无序结构中Mg和In原子共占据同一位置，据信这有利于稀土离子之间的能量转移，并通过在温度升高时维持发光而受益。在351nm紫外辐射激发下，MgInPO:Dy、MgInPO:TmDy和MgInPO:TmDy磷光体的测量绝对量子产率分别为70.50%、53.24%和52.31%。目前的工作表明，新型层状MgInPO作为单组分白色磷光体基质，对于近紫外激发的白光发光二极管（wLEDs）具有优异的热稳定性，是一个很有前途的候选材料。
